1. Field of the Invention
The present invention relates to an welding robot, and, in particular, to an welding robot capable of freely welding workpieces of many different shapes, under a wide variety of conditions by the movement within a specified operating area of a head on which a welding torch is mounted.
2. Description of the Prior Art
Conventionally, welding robots capable of welding workpieces of many different shapes, under a wide variety of conditions by the movement within a specified operating area of a head on which a welding torch is mounted are known. The movement of the head and the like of this type of welding robot is usually carried out under the control of a control device such as a computer or the like. Accordingly, it is necessary to create a specific program corresponding to the act of the movement to cause the head to move with a specified positioning precision (for example, with an error of less than 0.1 mm) based on a specified welding cycle.
However, in a conventional welding robot, because the head is caused to move merely by inputting the program even though the structure required to cause the head and the various parts of the head to move is very complicated, it is difficult to accurately position the head over the workpiece. Accordingly, it is difficult to draw up the required program working at a desk. Usually, the welding robot is caused to learn the operation at the actual workpiece, for example, by all types of `teaching` operations. Accordingly, this gives rise to the problem to waste time for works other than the welding, and the operating efficiency drops. In addition, it becomes impossible to draw up an operating program on a computer with the assistance of CAD-CAM or the like, and drawing up a welding program for a workpiece with a complicated shape becomes very difficult.